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<title>Chmod Task</title>
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<h2 id="chmod">Chmod</h2>
<h3>Description</h3>
<p>Changes the permissions of a file or all files inside specified directories. Right now it has
effect only under Unix or NonStop Kernel (Tandem).  The permissions are also UNIX style, like the
argument for the <kbd>chmod</kbd> command.</p>
<p>See the section on <a href="../dirtasks.html#directorybasedtasks">directory based tasks</a>, on
how the inclusion/exclusion of files works, and how to write patterns.</p>

<p>This task holds an implicit <a href="../Types/fileset.html">FileSet</a> and supports all of
FileSet's attributes and nested elements directly. More sets can be specified using
nested <code>&lt;fileset&gt;</code> or <code>&lt;dirset&gt;</code> (<em>since Apache Ant 1.6</em>)
elements.</p>

<p><em>Since Ant 1.6</em>, this task also supports
nested <a href="../Types/filelist.html">filelist</a>s.</p>

<p><em>Since Ant 1.7</em>, this task supports
arbitrary <a href="../Types/resources.html#collection">resource collections</a> as nested
elements.</p>

<p>By default this task will use a single invocation of the underlying <kbd>chmod</kbd> command.
If you are working on a large number of files this may result in a command line that is too long for
your operating system.  If you encounter such problems, you should set the <var>maxparallel</var>
attribute of this task to a non-zero value.  The number to use highly depends on the length of your
file names (the depth of your directory tree) and your operating system, so you'll have to
experiment a little.  POSIX recommends command line length limits of at least 4096 characters, this
may give you an approximation for the number you could use as initial value for these
experiments.</p>

<p>By default this task won't do anything unless it detects it is running on a Unix system.  If you
know for sure that you have a <kbd>chmod</kbd> executable on your <code>PATH</code> that is
command line compatible with the Unix command, you can use the task's <var>os</var> attribute and
set its value to your current OS.</p>

<p>See the <a href="setpermissions.html">setpermissions</a> task for a platform independent
alternative.</p>

<h3>Parameters</h3>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>file</td>
    <td>the file or single directory of which the permissions must be changed.</td>
    <td rowspan="2">Exactly one of the two, unless
      nested <code>&lt;fileset|filelist|dirset&gt;</code> elements are specified</td>
  </tr>
  <tr>
    <td>dir</td>
    <td class="left">the directory which holds the files whose permissions must be
      changed.<br/><strong>Note</strong>: for backwards compatibility reasons <code>&lt;chmod
      dir="some-dir"/&gt;</code> will only change the permissions on <samp>some-dir</samp> but not
      recurse into it, unless you also specify any patterns.</td>
  </tr>
  <tr>
    <td>perm</td>
    <td>the new permissions.</td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>includes</td>
    <td>comma- or space-separated list of patterns of files that must be included.</td>
    <td>No; defaults to all (<q>**</q>)</td>
  </tr>
  <tr>
    <td>excludes</td>
    <td>comma- or space-separated list of patterns of files that must be excluded.</td>
    <td>No; defaults to default excludes or none if <var>defaultexcludes</var> is <q>no</q></td>
  </tr>
  <tr>
    <td>defaultexcludes</td>
    <td>indicates whether default excludes should be used or not (<q>yes|no</q>).</td>
    <td>No; defaults to <q>yes</q></td>
  </tr>
  <tr>
    <td>parallel</td>
    <td>process all specified files using a single <kbd>chmod</kbd> command.</td>
    <td>No; defaults to <q>true</q></td>
  </tr>
  <tr>
    <td>type</td>
    <td>One of <q>file</q>, <q>dir</q> or <q>both</q>. If set to <q>file</q>, only the permissions
      of plain files are going to be changed. If set to <q>dir</q>, only the directories are
      considered.<br/><strong>Note</strong>: The type attribute does not apply to
      nested <code>dirset</code>s&mdash;<code>dirset</code>s always implicitly assume type to
      be <q>dir</q>.</td>
    <td>No; default is <q>file</q></td>
  </tr>
  <tr>
    <td>maxparallel</td>
    <td>Limit the amount of parallelism by passing at most this many sourcefiles at once.  Set it to
      negative integer for unlimited.  <em>Since Ant 1.6</em>.</td>
    <td>No; defaults to unlimited</td>
  </tr>
  <tr>
    <td>verbose</td>
    <td>Whether to print a summary after execution or not.  <em>Since Ant 1.6</em>.</td>
    <td>No; defaults to <q>false</q></td>
  </tr>
  <tr>
    <td>os</td>
    <td>list of Operating Systems on which the command may be executed.</td>
    <td>No</td>
  </tr>
  <tr>
    <td>osfamily</td>
    <td>OS family as used in the <a href="conditions.html#os">&lt;os&gt;</a> condition.</td>
    <td>No; defaults to <q>unix</q></td>
  </tr>
</table>
<h3>Examples</h3>

<p>Make the <samp>start.sh</samp> file readable and executable for anyone on a UNIX system.</p>
<pre>&lt;chmod file=&quot;${dist}/start.sh&quot; perm=&quot;ugo+rx&quot;/&gt;</pre>

<p>Make the <samp>start.sh</samp> file readable, writable and executable only for the owner on a
UNIX system.</p>
<pre>&lt;chmod file=&quot;${dist}/start.sh&quot; perm=&quot;700&quot;/&gt;</pre>

<p>Make all <samp>.sh</samp> files below <samp>${dist}/bin</samp> readable and executable for anyone
on a UNIX system.</p>
<pre>
&lt;chmod dir=&quot;${dist}/bin&quot; perm=&quot;ugo+rx&quot;
       includes=&quot;**/*.sh&quot;/&gt;</pre>

<p>Make all files below <samp>shared/sources1</samp> (except those below any directory
named <samp>trial</samp>) writable for members of the same group on a UNIX system. In addition, all
files belonging to a FileSet with <var>id</var> <samp>other.shared.sources</samp> get the same
permissions.</p>
<pre>
&lt;chmod perm=&quot;g+w&quot;&gt;
  &lt;fileset dir=&quot;shared/sources1&quot;&gt;
    &lt;exclude name=&quot;**/trial/**&quot;/&gt;
  &lt;/fileset&gt;
  &lt;fileset refid=&quot;other.shared.sources&quot;/&gt;
&lt;/chmod&gt;</pre>

<p>Keep non-owners from touching <code>cgi</code> scripts, files with a <samp>.old</samp> extension
or directories beginning with <samp>private_</samp>. A directory ending in <samp>.old</samp> or a
file beginning with <samp>private_</samp> would remain unaffected.</p>
<pre>
&lt;chmod perm=&quot;go-rwx&quot; type=&quot;file&quot;&gt;
  &lt;fileset dir=&quot;/web&quot;&gt;
    &lt;include name=&quot;**/*.cgi&quot;/&gt;
    &lt;include name=&quot;**/*.old&quot;/&gt;
  &lt;/fileset&gt;
  &lt;dirset dir=&quot;/web&quot;&gt;
    &lt;include name=&quot;**/private_*&quot;/&gt;
  &lt;/dirset&gt;
&lt;/chmod&gt;</pre>

<h3>Note on <var>maxparallel</var> attribute</h3>
<p>Some shells have a limit of the number of characters that a command line may contain.  This
maximum limit varies from shell to shell and from operating system to operating system.  If one has
a large number of files to change mode on, consider using the <var>maxparallel</var> attribute. For
example when using AIX and the limit is reached, the system responds with a warning: <code>"Warning:
UNIXProcess.forkAndExec native error: The parameter or environment lists are too long"</code>. A
value of about 300 seems to result in a command line that is acceptable.</p>
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